This invention relates generally to producing improved printing of face-to-face pages within a booklet and, more specifically, to a method for printing pages within a booklet to improve face-to-face appearance and the booklet produced thereby.
Customer acceptance of booklets assembled from duplex pages is sensitive to the consistency of appearance of opposing pages. Differences in color gamut, gloss, image size, and clarity are some of the problems encountered. Problems relating to cluster printing, that is, jobs assembled from separate machines include sheets with different gloss, color gamut, and image quality characteristics.
Tandem immediate duplex (xerographic) printers provide normal ordering of front sides on a first photoreceptor and back sides on a second photoreceptor, which also leads to similar problems. One example of such an apparatus is a tandem immediate duplex (color) xerographic (continuous) web printer. Another example is a tandem immediate duplex xerographic (cut sheet) printer, wherein images destined for the front sides of the physical sheets, i.e., the odd numbered pages, are imaged and developed sequentially on a first photoreceptor and images destined for the back sides of the physical sheets, i.e., the even numbered pages, are imaged and developed sequentially on a second photoreceptor. The physical sheets are fused twice; the first time in fuser #1 after transfer of the image on the front side of the sheet and the second time in fuser #2 after transfer of the image onto the back side of the sheet. Images on opposing pages have a different fused state and have been imaged/developed on different photoreceptor units. For example, an odd numbered page having an image developed on photoreceptor #1 that has been fused twice is opposed by an even numbered page having an image developed on photoreceptor #2 that has been fused only once.
Recirculating duplex printers having fusers present only the more subtle problem of differing fused state of opposing pages. This can lead to different gloss, different image shrinkage and/or misregistration of images. For example, a xerographic printer having a recirculating duplex paper path typically uses a fuser to fuse the image(s) to the paper. Images destined for the front sides of the physical sheets, i.e., the odd numbered pages, are imaged sequentially. After transfer of the first side image the physical page is inverted and recirculated. Images destined for the back sides of the physical sheets, i.e., the even numbered pages, are imaged sequentially. After transfer of the image destined for the back side, each physical page passes through the fuser again, bypasses the inverter and is stacked. The images on opposing pages in the stacker destined for a booklet have been fused a different number of times. For example, the image on page 14 has been fused once while the image opposing it, on page 15, has been fused twice.
A method in accordance with one embodiment includes producing a booklet from a multiple engine serial duplex printer, by:                ordering sequentially a first plurality of images on a first printing device;        feeding sequentially a plurality of two-sided sheets to the first printing device;        printing sequentially on one side of each of the plurality of two-sided sheets a corresponding one of the first plurality of images;        ordering sequentially a second plurality of images on a second printing device, such that when the second plurality of images is sequentially printed on a corresponding one of the other side of each of the plurality of two-sided sheets and alternate sheets in the sequence are inverted and stacked with alternate non-inverted sheets, images on opposing sides of the sheets are printed by the same printing device;        feeding sequentially the plurality of two-sided sheets to the second printing device;        printing sequentially on the other side of each of the plurality of two-sided sheets a corresponding one of the second plurality of images;        inverting alternated ones of the plurality of two-sided imaged sheets; and        stacking sequentially the inverted sheets and non-inverted sheets, so that images on opposing sides of the sheets are printed by the same printing device.        
A method in accordance with another embodiment includes producing a booklet from a multiple engine serial duplex printer, by:                ordering sequentially a first plurality of images on a first printing device;        feeding sequentially a plurality of two-sided sheets to the first printing device;        transferring sequentially on one side of each of the plurality of two-sided sheets a corresponding one of the first plurality of images;        fixing the image marked on each sheet;        ordering sequentially a second plurality of images on a second printing device, such that when the second plurality of images is sequentially fixed to a corresponding one of the other side of each of the plurality of two-sided sheets and alternate sheets in the sequence are inverted and stacked with alternate non-inverted sheets, images on opposing sides of the sheets are subject to the fixing process the same number of times and are printed by the same printing device;        feeding sequentially the plurality of two-sided sheets to the second printing device;        transferring sequentially on the other side of each of the plurality of two-sided sheets a corresponding one of the second plurality of images;        fixing the images marked on each sheet, the images corresponding to the first plurality images being fixed a second time and the images corresponding to the second plurality images being fixed a first time;        inverting alternated ones of the plurality of two-sided printed sheets; and        stacking sequentially the inverted sheets and non-inverted sheets, so that images on opposing sides of the sheets are subject to the fixing process the same number of times and are printed by the same printing device.        
A method in accordance with another embodiment includes producing a booklet from a recirculating duplex printer, by:                ordering sequentially a first plurality of images on a printing device;        feeding sequentially a plurality of two-sided sheets to the printing device;        transferring sequentially on one side of each of the plurality of two-sided sheets a corresponding one of the first plurality of images;        fixing the image marked on each sheet;        inverting sequentially a first pass of each one of the imaged plurality of two-sided sheets;        ordering sequentially a second plurality of images on the printing device, such that when the second plurality of images is sequentially fixed to a corresponding one of the other side of each of the plurality of two-sided sheets and alternate sheets on the second pass in the sequence are inverted and stacked with the alternate second pass non-inverted sheets, images on opposing sides of the sheets are subject to the fixing process the same number of times;        feeding sequentially the plurality of two-sided sheets to the printing device;        transferring sequentially on the other side of each of the plurality of two-sided sheets a corresponding one of the second plurality of images;        fixing the images marked on each sheet, the images corresponding to the first plurality images being fixed a second time and the images corresponding to the second plurality images being fixed a first time;        inverting alternate ones on the second pass of the plurality of two-sided printed sheets; and        stacking sequentially the inverted sheets on the second pass and the non-inverted sheets on the second pass, so that images on opposing sides of the sheets have been subject to the fixing process the same number of times.        
Another embodiment includes a booklet including a plurality of pages each having an image contained thereon wherein each image has been subject to a fixing process the same number of times as the image on an opposing page and wherein each image has been printed by the same printing device as the image on an opposing page.
Another embodiment includes a booklet including a plurality of pages each having an image printed thereon by a multiple engine serial duplex printer, wherein each image has been printed by the same printing device as the image on an opposing page.